List your debts, pick a strategy, and add any extra monthly payment to see months to debt-free, total interest, and the order each debt gets paid off.
| Order | Paid off |
|---|
Snowball pays off the smallest balance first regardless of interest rate, building momentum through quick psychological wins. Avalanche pays off the highest interest rate first, which minimizes total interest paid mathematically. Avalanche is always at least as cheap as snowball for the same debts — the question is really which approach you'll actually stick with.
Every debt gets its minimum payment each month. Any extra amount you specify, plus the minimum payments freed up from debts you've already paid off, goes entirely toward the current priority debt based on your chosen strategy — accelerating that one debt while others stay at their minimum.
Avalanche never costs more in total interest than snowball for the same debts and extra payment amount — but the difference can be small if balances and rates are fairly similar across your debts, in which case picking whichever keeps you motivated to keep paying is a completely reasonable choice.
Every payment splits between interest and principal, and early in a loan the interest share is at its largest. Any extra payment goes entirely to principal, which removes not just that amount from the balance but all the future interest that amount would have generated. That's why a modest overpayment shortens the term far more than it reduces the balance.
The effect compounds in your favour: a smaller balance next month means less interest charged, so a larger share of your normal payment goes to principal too. The benefit accelerates rather than staying constant.
On revolving debt, the minimum is typically a percentage of the balance plus that month's interest. Because it's a percentage, it falls as the balance falls — so progress gets slower exactly as you make headway. Fixing your payment at a constant amount instead of paying the shrinking minimum is usually a bigger win than refinancing to a lower rate.
The gap between them is usually smaller than people expect, and the method you actually follow beats the method that's optimal on paper. Our full comparison works through both with the same numbers.
Confirm your lender applies extra payments to principal rather than treating them as prepaid future instalments — some do the latter by default, which advances your due date without saving any interest. And check for prepayment penalties, which are uncommon on cards but do appear on some personal and auto loans.
One ordering point: if you have no emergency fund at all, building a small one first is usually right even at high interest, because the alternative to a cash buffer is more borrowing at the same rate the moment something breaks.
Not sure which strategy fits your situation? Read Debt Snowball vs. Avalanche for a full comparison with a worked example, or why credit card rates are still near 21% in 2026. Want the full financial picture beyond debt? Check your overall Net Worth. Federal student loans work differently from card debt and shouldn't be attacked the same way — the Income-Driven Repayment Calculator shows what RAP or IBR would charge before you decide to overpay them. The same ground is covered chapter by chapter in our book, From Paycheck to Portfolio. Clearing balances is also the fastest way to move a credit score — utilisation is 30% of it and recalculates every cycle.